A medical instrument including a catheter main body consisting of an elongated tube shaped body is used when performing various kinds of medical treatment in a lesion area generated in a biological lumen of a living body. For example, a medical elongated body such as a balloon catheter which performs treatment of widening a stenosed site generated in a biological lumen is generally known as this kind of medical instrument.
In general, the medical elongated body is delivered to the lesion area generated in the biological lumen by moving along a guide wire which has been previously introduced into the biological lumen. The medical elongated body has a tube body and includes a guide wire lumen for inserting a guide wire to be maneuvered in this manner. For example, refer to the disclosure in Japanese Patent Application No. 2013-116329.